I have gigabit ethernet connected to my PC, and I'm certain that it works properly, since when I run speed tests using the Speedtest by Ookla website it displays gigabit, and when I try with the Windows Store app it has the same results.
Web pages load quickly, streaming is effortless, and downloads through steam, or blizzard launcher etc are completely fine and very fast.
The only times when I notice an issue is when I download anything using Chrome (Or edge, which I tested), where I only get about 900kb/s, no more no less.
I've tried using wifi and ethernet, I've made sure there are no throttling settings enabled in Chrome, and have disabled all my extensions as well just to be sure, but still the same speeds.